During an x-ray examination electrons in the form of an electron beam are accelerated in an x-ray tube towards an anode and form a focus there which represents the source of the x-ray radiation, In a magnetic navigation of a catheter in blood vessels or in the heart of a patient or a laboratory animal known from DE 103 13 868 A, such an x-ray tube is operated during the x-ray examination in the variable foreign magnetic field necessary for navigation; In this way the electron beam is deflected by the foreign magnetic field so that the focus on the anode shifts and the x-ray radiation thus appears in a modified geometric image at an x-ray detector or an x-ray film In x-ray examination methods in which a number of x-ray images are created and evaluated against each other, the variable foreign magnetic field, despite an unchanged relative position of x-ray tube, examination object and x-ray detector or x-ray film, leads to image sections of the x-ray images offset against each other in each case.